The present invention relates in general to container closures that are constructed and arranged to threadedly attach to a container opening. More specifically, the present invention relates to a container closure that is vented to allow the entry of air into the container (to relieve a negative pressure) as some of the liquid contents of the container are removed by way of an exit port. This particular closure structure can be described as a double vent closure. While the intended contents of the container are primarily liquids, slurried products can also be dispensed, as will be described herein.
The present invention may find applicability in a variety of structural configurations and equipment, but the present invention is described in the context of an apparatus for dispensing a concentrated chemical in liquid form or a slurried product, such as those used for industrial cleaning processes. Additionally, the present invention is described in the context of a replaceable, sealed container that is intended to be flow coupled to a machine, such as an automatic dishwashing machine, for the delivery of a washing detergent to the machine.
U.S. Pat. No. 5,086,950 issued Feb. 11, 1992 to Crossdale et al. discloses a “liquid dispensing apparatus” that is described as an apparatus for dispensing liquid or slurried products for industrial cleaning processes. Since the present invention has a similar focus and applicability, though structurally different, U.S. Pat. No. 5,086,950 is incorporated by reference herein for its background discussion and its overall system environment explanation. The '950 patent describes the Background of the Invention in the following manner.
Conventionally, liquid detergents are supplied to customers in large drums and the detergent reservoir in the dishwashing machine is regularly filled up from the drums. This is a laborious and inconvenient method of keeping the dishwashing machine topped up and could result in spillage of the liquid, which is often caustic, onto the operator's hands.
Alternatively, the detergent may be supplied from a relatively large drum and pumped into the dishwashing machine along a tube or otherwise dispensed directly into the dishwashing machine. Such pumping systems often cause spillage of the detergents when the operator is disconnecting the reconnecting the pumping system to the supply drum.
An aim of one aspect of the present invention is to provide a system whereby the liquid product can be supplied in relatively small containers which are fitted directly to the operative part of a machine, for example the dispenser of a dishwashing machine, thereby minimizing or eliminating spilling and leakage. An aim of a further aspect of the invention is to provide a system whereby the liquid product can be easily and cleanly dispensed along a tube, again minimizing or eliminating spillage and soiling of the user's hands.
The present invention provides a novel and unobvious advance in the state of the art and an improvement over the closure described in the '950 patent. While the intended use for the present invention is part of a fluid dispensing system, it should be noted that the container to which the closure is attached can be fitted directly to the machine in an inverted orientation or used upright and connected by a conduit to the machine. The latter arrangement requires some type of pumping or suction structure in order to draw out fluid for delivery to the machine. In either configuration, a fluid delivery conduit or siphon tube is utilized. Since the container is sealed, a vacuum is created as the fluid contents are removed and the container must then be vented in order to relieve the interior negative pressure. This is part of the present invention. Ultimately, the liquid or slurry product in the container is able to be dispensed in a smooth flowing manner, without spillage or soilage of the hands of the user.
The vented closure, according to the present invention, functions as a self-contained, tamper-proof screw cap that is utilized after the container is filled with the selected fluid or slurry product. Included as part of the vented closure is a central diaphragm or septum with a precision slit and a guide ring portion as part of the cap for receiving and guiding a suction or siphon tube and including a pressure balanced vent valve. The proper functioning of the overall closure system including the vented closure and the container cooperate to secure the liquids and/or slurry products within the container from spillage, leakage, unauthorized access, and container paneling/collapse. All of this is accomplished with a consistent rate of dispensing without any clogging of the vent valve. The materials used for the container and vented closure, according to the present invention, have a broad range of chemical compatibility and exhibit resistance to fluid attack that might otherwise create performance problems. In particular, the sealing and venting umbrella valve that is disclosed herein is fabricated from a silicone rubber (polymer) that includes a self-bleeding filler that bleeds to the surface over time and provides advantageous material properties.
Ultimately, the present invention provides a novel and unobvious advance in the state of the art.